The human lumbar spine includes individual vertebras that are connected to each other via a three joint complex—the vertebral disc and two facet joints. Under normal circumstances these structures function to protect the neural structures and to allow us to stand erect, bear axial loads, and be flexible for bending and rotation. When disorders of the spine occur due to disease or trauma, one or more of these spinal structures may function abnormally resulting in pain. In these pathologic circumstances, surgery may be required to stabilize the spine, protect the neural structures, and to relieve patient discomfort. Spinal fusion works well because it stops pain due to movement at the facet joints and intervertebral discs, holds the spine in place after correcting deformity, and prevents instability and or deformity of the spine after spine procedures such as discectomies, laminectomies or corpectomies.
The use of posterior stabilization rods and pedicle screws in combination with the insertion of an intervertebral implant is an effective method of spinal fusion. However, the operating procedure for implanting pedicle screws and rods is very invasive, and can result in many different postoperative problems. Accordingly, it is desirable to provide alternatives to pedicle screws and rods that provide stabilization to augment the intervertebral procedure.